Mining bitcoin, as we know, consumes a lot of energy: the bellowing server farms are an affront to many people who care about sustainability. But these days there are clever ways to connect bitcoin miners to existing industries and even give them a push towards sustainability. A Dutch example comes from the greenhouse industry.

Dutch greenhouse growers are in a special position. They have an obligation from the government to get rid of gas before 2040. But how? Solutions such as geothermal energy are not available for all locations and many greenhouse horticulture companies already have combined heat and power (CHP) plants. These run on gas and provide heat for the greenhouse and CO2 for the plants. Some of the electricity generated is used for lighting, but a significant proportion is a by-product, which they feed back into the grid.

At the greenhouse, the Dutch company Sustainable Data Farming (SDF) adds a "loop" to the CHP: the electricity generated is used to power bitcoin miners. The heat released from the mining process has value here: it goes into the greenhouse. This is done by immersing the equipment in a bath of a so-called dielectric fluid. This is pumped around and releases its heat through a heat exchanger. According to SDF, this reduces gas consumption by about 40%.

Co-founder of SDF Jelmer ten Wolde was recently a guest on the BNR CryptoCast radio program, where he explained the process: "One could view the mined Bitcoin as the by-product. But it is a big part of the revenue. At the current gas price, about 55% of our revenue comes from bitcoin." Of course, the greenhouse grower benefits from this: the miners pay much better than feeding the unused electricity back to the grid.

Getting rid of the CHP

Ten Wolde continues by explaining that integrating miners into gas-powered CHPs can be an intermediate step toward the electric heating of greenhouses. "For small and medium-sized companies, electric heating is not yet cost-effective: the government only encourages it for companies that purchase 5 Megawatts or more. But in time we expect an overcapacity of sustainable production from sun and wind. That means cheaper electricity. At that point, electric heating may become feasible for greenhouse horticulture. By that time, companies can dispose of their CHPs and switch to a greenhouse that runs entirely on electricity, the heat for which comes from bitcoin mining. You can see it this way: we are providing a bridge to a future energy transition."

Incidentally, the Dutch initiative also has a counterpart in Sweden, where a greenhouse is heated by an air-cooled data centre.

Garbage collectors of the energy market

Another way bitcoin miners are doing business with the traditional energy market is in oil fields. The byproduct of oil fields, natural gas, is normally a waste product that is flared but can also be used as an input for the servers. That amounts to CO2 emission reductions of tens of percents.

In all these cases, bitcoin mines act as a kind of subsidy to capture residual energy that would otherwise be (largely) lost.

Read more about the energy consumption of Bitcoin and how it helps promoting a greener grid.