In September 2014 the city of Burlington in the US state of Vermont decided to purchase the Winooski One Hydroelectric Facility, a 7.4 megawatt hydro plant located on the Winooski River at the edge of the city. This was the final step that allowed the city to claim that 100% of their electricity consumption is met by deploying only renewable energy sources. This is considered to be a major achievement given that the city, with a population of 42,452 (2015), is the largest community to achieve such a target.
In order to match electricity supply with demand at all times, when for example the wind is not blowing or the water flow in the river is low, electricity from dispatchable non-renewable energy sources needs to be purchased to provide reliable supply. However many times the renewable electricity produced by the local electricity provider Burlington Electric Department (BED) exceeds local demand and it is therefore sold to neighboring regions. Throughout a year this extra renewable electricity exceeds the amount purchased from non-renewable sources. Renewable electricity credits are also purchased by BED to satisfy this 100% yearly target. Therefore, it can be legitimately stated that 100% of the overall yearly electricity demand of Burlington is met through renewable energy sources.
The energy mix deployed in Burlington involves mainly biomass, covering up to 60% of the energy consumption. This consists mainly of the Joseph C. McNeil Generating Station, a major power plant whose main feedstock consists of wood. The wood comes from within a range of 60 miles and 95% comes from logging residue and reject by-products of wood harvesting. The plant is equipped with air quality control devices that limit the particulate stack emissions to one-tenth the level allowed by Vermont state regulation. Wind energy from a nearby wind farm covers approximately 17% of the electricity consumption. The remaining electricity is mostly derived from small hydroelectric plants and other minor renewable sources such as solar, landfill methane and large hydro.
Following this achievement, the Vermont state has also set a target to meet 90% of its energy needs including electricity, heating and transport with renewable energy sources by 2050.
For further details: