Among the issues, the distributed generation (DG) community is concerned that DG is being unfairly penalized by imposed exit fees or departing load charges. Additionally, while DG owners are routinely charged standby rates for remaining connected to the grid, they are not recognized for the benefitsósuch as load reductionóthat DG brings to the grid.

Another concern is that fuel cell systems are not recognized for their clean technology and for providing a bridge toward hydrogen-based energy systems. Fuel cell systems fueled by natural gas are generally recognized as environmentally advantageous because they produce negligible harmful emissions. In some states, such as New York, fuel cells, even those fueled by natural gas, are treated as ìrenewableî because of their ultra-low emissions. However, other states do not consider fuel cells renewable. And even in states such as New York, fuel cells do not enjoy the full benefits of net metering, exemption from stand by rates, and no-cost interconnections that recognized renewable energy sources, such as photovoltaics, receive. Along with many others in the DG community, Plug Power is working toward transformation of these restrictive regulations through rulemaking committee participation and government advocacy.

Fuel cell system manufacturers find it extremely important to participate in interconnection rulemaking as well as codes and standards development to ensure that current technology is represented and fairly assessed. In order to accomplish this, Plug Power in conjunction with others has been involved with the Institute of Electrical and Electronic Engineers (IEEE) 1547 Standard for Interconnecting Distributed Resources with Electric Power Systems; the Underwriters Laboratories (UL) 1741 Standard for Inverters, Converters, and Controllers for Use in Independent Power Systems; New Yorkís Standardized Interconnection Rules; Californiaís Rule 21; Massachusettsís interconnection proposed rulemaking; the Federal Energy Regulatory Commissionís (FERC) proposed rulemaking; the National Association of Regulatory Utility Commissionersí (NARUC) procedures; and the National Fire Protective on Associationís (NFPA) 70-National Electrical Code requirements, among others.

There are several model interconnection standards, some of which were featured in a recent Fuel Cell Summit article (Vol. 4, Issue 1). New to the list are ones from Illinois and New Jersey. Also, just finalized is one from the Massachusetts Department of Telecommunications and Energy (to view the document, link to http://www.state.ma.us/dpu/restruct/competition/distributed_generation.htm) It was collaboratively developed by government organizations, utilities, concerned public groups, DG industry stakeholders, and others. Several model interconnection standards were evaluated including those from California, FERC, NARUC, New York, and Texas. Similar to the New York and Texas standards, an important feature of the Massachusetts proposal makes it relatively easy for small-scale, inverter-based technologies to interconnect on radial systems with no application or study fees. Utilities in Massachusetts have filed tariffs for adopting this procedure. This is an important step toward making the interconnection process simpler and less expensive in Massachusetts, thereby promoting the installation of DG systems, at least on radial systems.

A recent fuel cell system installation in New York took less than three weeks for interconnection approval with no interconnection fees. This successful interconnection experience immediately followed a period of hands-on oversight and rulemaking activity by the New York State Public Service Commission (NYPSC). Successful interconnection experiences like this are helping rule makers gain confidence in the fuel cell industry to simplify interconnection procedures.

Among the many hurdles remaining is the area of secondary distribution network interconnection. Interconnection on secondary networksówhere high-density urban areas could most benefit from DGóis being considered cautiously by utilities. Network protective devices generally are not set up to handle generation or current flow from the load side. However, when the DG capacity is small compared to the facility load where it is installed, inverter-based systems can be readily used without affecting network system reliability.

Radial distribution systems are generally installed in overhead configurations, whereas network systems have major equipment installed underground. The typical circuit configuration for each system is shown in the figures below. Radial systems have small utility pole-mounted secondary distribution transformers, while network systems have underground vaults for large distribution transformers. Additionally, radial systems are generally fed from one source, while network systems often have several sources. One final note: network systems have all loads fed from one common secondary bus, while radial systems do not.

Fortunately, utilities are moving beyond outright bans of generation on networks to allowing installation with specific terms and requirements (including capacity limits based on facility and feeder peak loads and limits on network protector cycling). However, requirements that include expensive engineering studies and additional metering, such as reverse power relays, are hindering the growth of DG where it is needed the most. [For more information on DG and networks, see Electrical Power Systems Quality, 2nd edition, by Roger C. Dugan et al. (New York: McGraw-Hill. 2002).]

Another hurdle complicating the interconnection process is the issue of export versus non-export. Many interconnections have been accomplished with little concern by utilities that small inverter-based DG systems will create problems generating to the grid. However, an industrial client recently experienced excessive demands for documentation and study of system impacts when interconnecting with the utility. The systems were installed at very large facilities with no possibility of generation to the grid. It is important for utilities to know how much generation is connected to the grid, but when the inverter-based generator is a tiny fraction of the facility load, the grid will never see it. Again, more experience will encourage the adoption of more simplified interconnection procedures.

What the best interconnection rules have in common are (1) precertification of equipment and testing and (2) simplified review of system impacts.

Many interconnection standards include a process that allows preapproved or precertified equipment to be interconnected faster, easier, and less expensively. Preapproved equipment must be certified by a nationally recognized testing laboratory to a standard, such as UL 1741. Typically, the manufacturer works with the regulator to provide equipment specifications and certification proof, such as test reports. This can save much time and effort in trying to convince every utility that the DG equipment is safe and will not harm the distribution system. Precertified DG equipment can be interconnected without extensive review of system impacts.

Recently, Plug Power worked with NYPSC to list a new inverter as an approved type-tested interconnection device (to view the NYPSC Web site, link to www.dps.state.ny.us/distgen.htm).

The procedure and time to gain approval varies widely from state to state, but implementation has improved significantly over the last few years. In the past, and currently in some states, it can take several months. In the New York case it took one week, an incredibly short time period. A few interconnection standards, including FERC and Massachusetts, allow state-to-national or state-to-state reciprocity for approved equipment. In most cases, reciprocity does not exist and the preapproval process has to be repeated with every regulator. This practice further underscores the need for a national interconnection standard.

A national interconnection standard is closer to reality with FERCís rulemaking process moving ahead and the IEEE 1547 standard recently reaching completion. Adoption of the IEEE 1547 standard is a key to consistency of interconnection rules. The benefits from DG are being realized, and support for the industry is increasing. The DG rules, codes, and standards are now significantly improved, and continued efforts are helping eliminate the barriers to DG commercialization. The light at the end of the tunnel is approaching, but there remains some distance to cover. The DG community must continue its efforts to improve existing standards and work toward making a national interconnection standard a reality.

Author LISA POTTER is a senior electrical engineer with Plug Power Inc.

DE - July/August 2004