On Easter Monday 2021, 60% of all electricity in the Netherlands was generated sustainably. A record. A few days earlier, green power generation peaked at 77% for one hour. Also a record. The intention is for such percentages to become normal. The share of green energy in the energy mix is increasing every year, so dependence on wind and solar power is increasing. We are already seeing energy prices fluctuate; on windy and sunny days, electricity is a lot cheaper than on cloudy, windless days. As a company, you use this to your advantage by storing energy when costs are low. How does this work?
The advantage of energy storage
For the electrification of, say, a factory, you need a number of e-boilers and industrial heat pumps. E-boilers replace gas-fired steam boilers. Industrial heat pumps, on the other hand, can convert waste heat of 30-40 degrees which is not being used, to 120 degrees, making it usable for the processes. Electricity is now often more expensive than natural gas. So electrifying your plant doesn’t always lead to a strong business case. But then energy storage comes into play. It allows you to capitalize on low energy prices, collecting energy at the cheapest moments and using it again later, when the price is higher. So, what storage options are available?
Storage in water tanks
The easiest and cheapest way to store energy is in water. The disadvantage is that storage can only be up to 100 degrees. You can also store water under pressure, economically to a maximum of 160 degrees. In some cases, that can make all the difference. However, many industrial processes require a higher temperature. Heat storage in water falls short of that. But fortunately, there is stone.
Back to the Stone Age?
Stone – we hear you ask? Walk across your patio tiles on a warm, sunny day, and you immediately understand its potential. There are already stone storage systems on the market that can store heat up to 800 degrees. For example, basalt, which has a high density per cubic meter, can be used in several ways. One way is through a heating element that runs through the basalt block: You get the heat out through an open tube, through which you run oil or steam. The other way is by heating air to 850 degrees and then blowing it into the basalt block with large fans. The fans are then used to extract the heat at a later stage.
Better business case
Energy storage is not something for the future, its ready to be implemented. We are already seeing that our calculation models give better results when a certain form of energy storage is taken into account. What works varies, from client to client. One example, is using basalt and hot air to take an industrial plant off natural gas. We developed a solution using a basalt block measuring 40 x 20 x 10 meters and fans the size of a shipping container. This let the client actually save costs!
The holy heat battery
A real giant battery is not (yet) an option, as it is too expensive. However, the search for the holy grail in the field of storage is in full swing worldwide. A good example is Israel, where work is being done on a super-efficient heat battery made of volcanic material. Pieces of volcanic rock are compressed into a block that is 12 meters long. This giant shashlik is then heated with an electric coil. TransitionHERO currently has more than 15 types of thermal storage solutions in its database, ready to change the world.
Are you interested in energy storage? Our engineers will be happy to tell you more.