Are thermal batteries an alternative to lithium-ion?
Even those with a passing interest in the energy industry would have heard of lithium-ion batteries, seen by many as the solution for powering the electric vehicle battery revolution. But there may be less well-known and potentially more effective alternative in thermal batteries.
The basic principle of thermal battery is simple. Electric resistance coils heat an inexpensive thermal storage medium (silica sand) using low-cost excess electricity, such as intermittent solar and wind power sources.
Energy is stored as ultra-high temperature heat (up to 1000℃/1850℉) – at a fraction of the cost of batteries. Whenever needed, a specialised turbine reconverts the heat to electricity. An innovative turbine can do this without combustion, as atmospheric-pressure air is passed through the “Thermal Storage” and drives the “Turbine” to generate electricity.
By adding a combustor, the battery can also produce even more dispatchable backup power, ideally using an emission-free fuel such as green hydrogen in the combustion process. This is also how the battery can provide spinning reserves.
Thermal's prospects have recently been enhanced by a new study from Arizona State University (ASU), which evaluated market opportunities for Swedish cleantech company TEXEL Energy Storage and found TEXEL offers a lower cost to lithium-ion batteries for the American market.
The study shows TEXEL's technology could be successful in California and suggests the company pursue all customer segments of the California market for coupled storage and generation applications, where TEXEL's technology, paired with solar PV, costs at average of 8 cents per kWh (5 cents incl. thermal) compared to 14 cents per kWh for solar PV and lithium-ion for large commercial and industrial-scale applications.
In New York, price differences between off-peak and on-peak energy rates are sufficiently great enough to create an opportunity for using TEXEL in residential and commercial markets when considering storage arbitrage – essentially charging batteries with low grid prices and discharging batteries to avoid higher, on-peak grid prices. For example, TEXEL can yield a delivered residential average electricity cost at 7 cents per kWh compared to lithium-ion at 14 cents per kWh.
Also, the report highlights an opportunity for the Power Purchase Agreement (PPA) market with coupled storage and generation. A recent 4-hour lithium-ion storage plus solar PPA yielded a blended cost of $43 per MWh compared to a $26 per MWh cost that could be possible with a 4-hour TEXEL plus solar PPA.
Lars Jacobsson, Founder and CEO of Swedish cleantech company Texel Energy Storage - which intends to manufacture the technology in the US - said the ASU study shows that TEXEL has a great opportunity in the American market and has "the right focus" in targeting California. "It also shows that our technology is a hugely competitive alternative to existing energy storage technologies, such as lithium-ion batteries. An economically viable and circular energy storage technology is needed to be able to create the change in future energy production and distribution and to reach future goals and legislation in states like California."
TEXEL metal hydride thermochemical energy storage technology provides an emerging solution that can store energy and provide both electrical and thermal output. Furthermore, the TEXEL storage chemistry is made from environmentally benign chemicals which are stable for long durations and have expected life cycles of 40 years.
These chemicals can be salvaged and recycled, which helps creates a circular market mechanism to reduce environmental impact compared to single-life batteries that have little to no recycling. In addition, the salvage value at the end of cycling life enhances project economics by recovering a portion of the capital investment.
"The transition to a low-carbon, sustainable energy system, and evolution to a zero-carbon future, will require ultra-low-cost storage manufactured from environmentally benign materials that are stable for long durations without degradation and energy loss and are recyclable and circular. TEXEL's storage technology provides an emerging solution, which not only stores energy but can provide both electrical and thermal output," said ASU Associate Professor Nathan Johnson, Director of the Laboratory for Energy And Power Solutions (LEAPS) and primary investigator for the study.
The study's findings also indicate opportunities for TEXEL to provide cost-competitive, sustainable, and reliable power to other regions.
The electric vehicle (EV) market is growing rapidly and has even proved resilient to COVID-19 related shutdowns, seeing year-on-year growth throughout 2020, which in turn is sparking major innovation in the batteries sector.
Battery Resourcers, a vertically integrated lithium-ion battery recycling and manufacturing company, recently announced an agreement with American Honda Motor Co. to recycle Honda & Acura Electric Vehicles (EV) batteries. Honda's batteries will initially be processed by the company's recently expanded site in Worcester, Mass. and later at a new commercial scale plant that will be operational in the spring of 2022. The new site which will be capable of processing more than 20 million pounds of batteries.
Albemarle Corporation has opened its Battery Materials Innovation Center (BMIC) located at its Kings Mountain, North Carolina, site. It is expected to be fully operational this month and will support Albemarle's lithium hydroxide, lithium carbonate and advanced energy storage materials growth platforms. It has been equipped to enable synthesis of new materials, material properties characterisation and analysis, material scale-up capabilities, and material integration into battery cells for performance testing.
Comau has developed a high-volume module manufacturing line to produce new generation lithium-ion batteries for Leclanché, a leading global provider of energy storage solutions for the heavy transport, naval and railway industries. The highly automated line is the result of a simultaneous engineering process and combines industrial robots, vision systems, laser welding, and the automated in-line validation of joints via AI.
It will allow Leclanché to produce up to six times the company’s current capacity, reaching an output of more than 60,000 modules per year. The solution is also expected to reduce costs by up to 20%, support 50 different product configurations and save Leclanché valuable time when introducing new formats into the manufacturing line.
In May, a new battery from 247Solar Inc., a spinoff of MIT, was unveiled - operating like an electrochemical battery but with significant advantages at longer durations. It is designed to replace traditional diesel gensets at remote mines, and the company claims it provides 24/7 highly reliable operation with higher renewables penetration, significant fuel savings, and dramatically lower lifetime operating costs.
The IEA has set an ambition for 30% of the world’s road fleet to electrify by 2030. This translates to 44 million EVs, a mobility revolution which will need to be powered by approximately 220 billion lithium-ion battery cells. But as manufacturers strive for sustainable efficiencies, thermal batteries may also have their place.
Industry movement with heat decarbonisation
It is estimated that the heat network market requires approximately £30 billion of investment by 2050 to meet the UK Government’s net zero targets, and the decarbonisation of heat has been highlighted as a particular challenge.
The Climate Change Committee’s Sixth Carbon Budget states the UK should target 20% of UK heat demand through low-carbon heat networks by 2050 - but as with most discussions surrounding mass decarbonisation, even reaching that target won't be an easy task. In the UK approximately 40% of energy consumption and 20% of GHG emissions are due to the heating and hot water supply for buildings.
The International Energy Agency (IEA) estimate that globally, around half of all energy consumption is used for providing heat, mainly for homes and industry.
Source: Heat Trust
This week saw some positive movement, however, with gas distribution company SGN and UK renewable energy solutions provider Vital Energi announcing a 50:50 joint venture, which will create an Energy Services Company (ESCO) representing utility infrastructure and heat network providers.
This includes delivery of heat to developments planned by SGN’s property arm, SGN Place, and the local vicinities where there is a demand for low-carbon heat.
The objective is to supply new and existing residential, industrial and commercial facilities and development activity is already underway for two projects in Scotland and the South East, with another 20 in the pipeline. SGN is looking to develop alternative heat solutions alongside its core gas distribution business and expand into the growing district heating market, recognising the future of heat is likely to include a mix of technological solutions and energy sources.
Vital Energi is seeking to expand into asset ownership opportunities to complement its core design, build and operations businesses. The complementary skillsets of both organisations will offer a compelling proposition for developers, commercial and industrial users and public sector bodies seeking low-carbon heat solutions.
SGN’s Director of Commercial Services and Investments Marcus Hunt said: “Heat networks are likely to play an increasing role in the delivery of UK heat in the context of net zero. The creation of this joint venture with market-leading Vital Energi enables us to build a presence in this emerging market, delivering new heat infrastructure and supporting decarbonisation.”
Nick Gosling, Chief Strategy Officer at Vital Energi, said: “Combining the resources, expertise and know-how of both organisations will allow us to play a major role in delivering the UK’s transition to low and zero-carbon heat.”
In March, the European Marine Energy Centre (EMEC) starting collaborating with Highlands and Islands Airports Limited (HIAL) to decarbonise heat and power at Kirkwall Airport through green hydrogen technology. 2G Energy was selected to deliver a CHP plant which generates heat and electricity from 100% hydrogen.
Heat decarbonisation options
The Energy & Climate Intelligence Unit (ECIU) highlights the following options for decarbonising heating.
Use renewable electricity to generate heat in the home. As power sector emissions fall, emissions associated with electric heating are decreasing rapidly.
Low carbon gases
Replace natural gas that most homes use for heating with hydrogen, which releases energy but not carbon dioxide, the only waste product is water. Biomethane is also an option as it produces less carbon than natural gas over a full lifecycle.
For hydrogen to work, the pipes in the national gas grid would need to be replaced and home boilers would need to be adapted or changed. This is possible but could incur considerable cost.
Biomethane is chemically identical to methane from natural gas, so is suited to existing infrastructure and appliances. It is unlikely, however, that it can be produced in sufficient quantities to replace fossil gas entirely.
A hybrid system combining both electrification and hydrogen is a third option. Here, heat pumps could be used to meet the majority of heat demand, with a (low carbon) gas boiler taking over in extremely cold weather. Advantages of this approach include helping establish a market for heat pumps while hydrogen is developed to displace natural gas in the hybrid system eventually, and the ability to call on hydrogen when heat demand is at its very highest.
Heat networks connect a central heat source to a number of buildings via a series of underground hot water pipes, and are popular in countries such as Denmark, where heat networks supply 63% of households. The Government expects the heat networks market in the UK to grow quickly to supply up to 20% of heat demand over the next decade or so, investing £320 million into its flagship Heat Networks Investment Project to help get this underway.
Heat networks work particularly well in built-up urban areas or industrial clusters where there is a large and concentrated demand for heat. Over time, it is thought that if the central heat source can be low carbon, then there is the opportunity to ensure that multiple homes and buildings are decarbonised at once.
Biomass can be used to reduce emissions when used instead of more polluting fuels like oil in off gas grid properties. Support for biomass boilers has been available since 2011 via the Renewable Heat Incentive (RHI), but take-up has been low.
Supply constraints also restrict the role that biomass – burning solid material such as wood – can play. In any case, according to the Committee on Climate Change, this resource may be better used in other sectors of the economy such as construction, where it provides carbon storage without the need for CCS and reduces demand for carbon-intensive materials such as steel and cement.
The Energy Transitions Commission (ETC)'s latest report sets out how rapidly increasing demand for bioresources could outstrip sustainable supply, undermining climate mitigation efforts and harming biodiversity, unless alternative zero-carbon options are rapidly scaled-up and use of bioresources carefully prioritised.
"Alternative zero-carbon solutions, such as clean electrification or hydrogen, must be developed rapidly to lessen the need for bio-based solutions," it states.
The overall decarbonisation of industry is another major challenge, especially among four sectors that contribute 45 percent of CO2 emissions: cement, steel, ammonia, and ethylene, according to a McKinsey report.
The process demands reimagining production processes from scratch and redesigning existing sites with costly rebuilds or retrofits. Furthermore, companies that adopt low-carbon production processes will see a short- to mid-term increase in cost, ultimately placing them at an economic disadvantage in a competitive global commodities market.
Ken Hunnisett is Project Director for the Heat Network Investment Project (HNIP)’s delivery partner Triple Point, which is the delivery partner for the government's Heat Network Investment Project, which is responsible for investing up to £320million in strategic, low-carbon heat network projects across England and Wales.
He is calling for the urgent need to invest in the development of new heating infrastructure to support the nation’s decarbonisation effort. So far £165m of HNIP funds have prompted £421m CAPEX, providing more green jobs as the UK economy eases from the lows sustained from the pandemic.
Decarbonising the UK's heating infrastructure is critical if we are to reach our net-zero goals and it’s crucial that progress is made in this decisive decade, he added.
"Heat networks are a part of the lowest-cost pathway to decarbonising our homes and workplaces in the future but are also the bit of the jigsaw that we can be putting into place now," he said. "Penetration into the UK market is still low, despite heat representing 37% of UK greenhouse gas emissions, the largest single contributor by some way. Funding needs to be urgently directed towards reducing the environmental impact of the residential sector, particularly given the slow pace of the decline in residential emissions in comparison to those of business and transport."
Currently, just 3% of UK buildings are serviced by heat networks. "Further investment in this industry, using public and private funds, will not only drive wider sustainability targets but will boost the economy by providing more green jobs as the country emerges from the pandemic," he said.