DumpToExcel.cs

using System.Collections.Generic;
using System.IO;
using OfficeOpenXml; // (EPPLus - http://epplus.codeplex.com/)

namespace OfficeReports
{
    public static class DumpToExcel
    {
        public static void Dump<T>(IEnumerable<T> data, string outputFilename)
        {
            var fileInfo = new FileInfo(outputFilename);

            using (var package = new ExcelPackage(fileInfo))
            {
                var worksheet = package.Workbook.Worksheets.Add("Report");

                worksheet.Cells["A1"].LoadFromCollection(data, true);

                package.Save();
            }
        }
    }
}