Powering your home from sunlight is a dream shared by many, but cost-prohibitive for most. Solar energy might be free, but only after you pay for the panels, inverters, and storage systems, and pay someone to install it all. But what if you could subsidize some of the upfront cost by agreeing to sell back a fraction of your power to the grid? That’s the idea behind CrowdNett, a new energy service announced today by Eneco in The Netherlands.

An estimated 400,000 homes in The Netherlands already have solar panels installed. Eneco is offering those homes discounted Tesla Powerwalls — €4,500 euro installed, instead of €7,000 — in an effort to build a "virtual power plant" of 400 networked batteries. The power can then be tapped as reserve capacity to help national grid providers cope with constant fluctuations on grid load, reserves usually provided by environmentally unfriendly sources like gas- or coal-fired power plants. CrowdNett participants will receive a payment of €450 a year for a guaranteed period of five years in return for 30 percent of each Powerwall’s capacity — an amount "you will barely notice in everyday practice," according to Eneco. Ampard will provide the software that redirects CrowdNett power reserves back to the grid, as the company has already done in its home country of Switzerland.

To be eligible for CrowdNett, homes must have solar panels installed already, a smart meter in place, a "decent internet connection," and enough space to mount a Tesla Powerwall. Oh, and they must reside in the Netherlands, though Eneco has plans to bring the service to all of Europe in the future.