海角视频

GeoMicroDistrict Feasibility Study

Boston, MA, USA

海角视频 was selected by Home Energy Efficiency Team (HEET), a Boston-based nonprofit, to lead the development of an innovative GeoMicroDistrict Feasibility Study, which explored the potential of replacing natural gas infrastructure with a network of neighborhood-scale district heating systems or 鈥淕eoMicroDistricts.鈥�

The goal of the Study was to assess the feasibility of designing, developing, implementing, and scaling up these systems in the Greater Boston area to reduce reliance on natural gas and move towards renewable energy sources.

The goal is to replace to replace 6,000 miles of aging and leaking gas pipes with and interconnected district-scale renewable energy system

Massachusetts to reduce emissions 80% from 1990 levels by 2050, and Carbon Free Boston seeks to achieve carbon neutrality for the city by 2050

Challenge

In 2019, 97 percent of natural gas pipelines in the U.S. were made of plastic or steel. Cast and wrought iron pipes make up the remaining 3 percent and are among the oldest gas lines in the country. Nearly half of all iron pipes are concentrated in four states including Massachusetts, New York, New Jersey, and Pennsylvania. If cast iron (and bare steel pipelines) are left in the ground beyond their service life instead of being replaced, utilities have to spend millions of dollars repairing leaks on old pipelines. When left unattended, leaking gas pipes release methane which is a highly combustible gas that poses significant health, public safety, and environmental risks.

Massachusetts has the second oldest gas infrastructure system in the country, with 6,000 miles of aging and leak prone pipes, which make up 26 percent of the State鈥檚 gas system. It is estimated that repairing and replacing the State鈥檚 leaking gas system can cost taxpayers over $9 billion over next 20 years. This does not include the price of lost gas that customers and businesses already pay in their monthly bills, which is estimated at $90 million per year in Greater Boston area alone.

The Home Energy Efficiency Team (HEET), a local environmental non-profit, began exploring potential substitutes for gas infrastructure. Long known for their work on energy efficiency retrofits and methane leak studies in Massachusetts, HEET wanted to explore an alternative business model where customers could purchase renewable thermal energy, instead of natural gas. In early 2019, HEET selected 海角视频 to lead a Feasibility Study to assess the replacement of aging natural gas infrastructure with a network of ground source heat pumps (GSHP).

Solution

The goal of the Study was to assess the feasibility of designing, developing, implementing, and scaling up these systems in the Greater Boston area to reduce reliance on natural gas and move towards renewable energy sources. The study focused on the use of ground-source heat pump technology, which uses electricity to transfer heat from the ground to a network of hot water pipes, to provide heating, and potentially cooling, for the buildings within each District. Ground-source heat pump technology is highly efficient and, when paired with clean electricity, is considered a renewable heat source.

Working with HEET and their network of stakeholders and technical advisors, which includes experts from local utilities, academic institutions, and community groups, the 海角视频 Cities team developed additional criteria to assess the potential impacts of implementing GeoMicroDistrict systems based on a range of sustainability, health and safety, and social and economic indicators.

海角视频 also developed guidelines for selecting and sizing system components based on site and building characteristics and their associated costs. A series of case studies was developed to identify best practices and lessons learned from other communities and jurisdictions. This study is intended as the first step in developing an alternative system, addressing economic and environmental risks while exploring options for new business models for utilities to invest in renewable district heating, rather than maintain aging natural gas infrastructure.

Value

The Study concluded that interconnected GeoMicroDistricts can provide nearly 100 percent of the annual thermal loads in low to medium density residential and mixed-use commercial areas. High density neighborhoods would require supplemental heating and cooling energy. The Study strongly advocates for a utility-scale approach wherein existing gas companies install, operate, and maintain the GeoMicroDistricts. As the customer base increases, the load diversity, efficiency, and economies of scale would improve.

Furthermore, the utility would also be responsible for scaling and managing system capacity while integrating thermal energy storage and backup energy systems, as needed.